Dear Frank! It seems for "normal_main" that you never reach 0.04 eV/Angstrom. How to fix that? And here is mt result (seems that MD.MaxCGDispl 0.15 Ang and DM.Tolerance 0.00001 behave better).
Best wishes, Maxim. 2013/11/22 <fma...@icp.uni-stuttgart.de> > A fluctuation in max. forces is normal. Attached is a max. force graph of > a few CG geometry optimizations I did of isolated molecules. > > Further details are in the following PDF: (keyword EggBox Effect) > http://www.home.uni-osnabrueck.de/apostnik/Lectures/SIESTA-tuto.pdf > > So the lower the max. force is, the less CG steps are required in my > experience and only then can you achieve low MD.MaxForceTol values. > > To reduce the max. forces you have to increase the finess of the real > space grid, by either increasing the MeshCutOff value or making use of > GridCellSampling: > > http://departments.icmab.es/leem/siesta/Documentation/Manuals/siesta-3.1-manual/node47.html > > > Best wishes, > Frank > > > > I'm doing geometry optimisation if I correctly set it (as I understand > > it's > > by default) > > > > Best Wishes, Maxim. > > > > > > 2013/11/22 Herbert Fruchtl <herbert.fruc...@st-andrews.ac.uk> > > > >> Just to clarify: You are doing MD, not a geometry optimisation, and you > >> are surprised that the forces don't go to zero? What are you trying to > >> find? For a minimum energy structure, you need a geometry optimisation. > >> In > >> an MD simulation the total (potential+kinetic) energy should remain > >> constant (depending on your ensemble...), but the forces will vary. > >> > >> Herbert > >> > >> > >> On 22/11/2013 08:58, Максим Арсентьев wrote: > >> > >>> Dear Sebastian! > >>> > >>> My calculations convverge at each MD cycle (about 300-400 SCF cycles), > >>> but max force oscillate (about 0.1-0.04 eV/anstrom) and I can not > >>> finish > >>> MD, and am already at 63 cycle and the calculation cycle is still > >>> going, > >>> although the system is quite large and contains 47 atoms. My counter > >>> question to all: does this oscillation of forces normal? > >>> I would like to strict DM.Tolerance to 0.00001 (it is VERY important to > >>> accurate calculation of forces) and to limit MD.MaxCGDispl . > >>> > >>> Best Wishes, > >>> Maxim > >>> > >>> > >>> 2013/11/21 Sebastian Caicedo Davila > >>> <sebastian.caic...@correounivalle.edu.co > >>> <mailto:sebastian.caic...@correounivalle.edu.co>> > >>> > >>> > >>> Hello Diana!! > >>> > >>> Thanks a lot for your suggestion! I'll give it a try and maybe I'll > >>> be bothering you again, if it is not an imposition, of course. > >>> > >>> Gracias de nuevo, y saludos desde tu tierra! > >>> > >>> Sebastian Caicedo Davila > >>> Bionanoelectronics Research Group > >>> School of electrical and electronics engineering > >>> Universidad del Valle > >>> Cali - Colombia. > >>> > >>> > >>> > >>> On Nov 21, 2013, at 11:02 AM, <d.otalv...@utwente.nl > >>> <mailto:d.otalv...@utwente.nl>> <d.otalv...@utwente.nl > >>> <mailto:d.otalv...@utwente.nl>> wrote: > >>> > >>> Hello Sebastian, > >>>> > >>>> I have had similar problems with convergence of the scf cycle. > >>>> They were solved when I changed from Pulay mixing to Broyden > >>>> mixing for the charge density. > >>>> > >>>> Usually if something doesn't converge in 250 cycles, it probably > >>>> never will. Also you can play with the DM.Tolerance. For very > >>>> difficult systems I set it to 0.0008 and then restart from that DM > >>>> file with a stringer convergence criterion. > >>>> > >>>> Here is the settings I am using for my calculations: > >>>> > >>>> #--------------------Convergence of SCF--------------------------- > >>>> ---- > >>>> MeshCutoff 200.0 Ry # Default value PW cutoff > >>>> for grid > >>>> > >>>> > >>>> MaxSCFIterations 250 # Maximum number of SCF > >>>> iter > >>>> DM.NumberBroyden 3 > >>>> DM.MixingWeight 0.01 # New DM amount for next > >>>> SCF cycle > >>>> DM.Tolerance 0.0001 # Tolerance in maximum > >>>> difference > >>>> DM.UseSaveDM .false. # to use continuation > >>>> files > >>>> > >>>> DM.NumberKick 100 > >>>> DM.KickMixingWeight 0.01 > >>>> #---------------------------------- > >>>> > >>>> Suerte! > >>>> > >>>> PS: yo tambien soy caleña! > >>>> > >>>> Diana M. Otálvaro > >>>> PhD Candidate > >>>> > >>>> Computational Material Science > >>>> MESA+ Institute of Nanotechnology > >>>> University of Twente. > >>>> Enschede, Nederland > >>>> ------------------------------------------------------------ > >>>> ------------ > >>>> *From:*siesta-l-requ...@uam.es <mailto:siesta-l-requ...@uam.es> > >>>> [siesta-l-requ...@uam.es <mailto:siesta-l-requ...@uam.es>] on > >>>> > >>>> behalf of Максим Арсентьев [ars21031...@gmail.com > >>>> <mailto:ars21031...@gmail.com>] > >>>> *Sent:*Wednesday, November 20, 2013 7:29 AM > >>>> *To:*siesta-l@uam.es <mailto:siesta-l@uam.es> > >>>> *Subject:*Re: [SIESTA-L] Convergence problem on heterostructure. > >>>> > >>>> > >>>> I forgot to tell you - besides DM.MixingWeight 0.05 I also set > >>>> PAO.EnergyShift to 65 meV as > >>>> herehttp://www.nature.com/nnano/journal/v7/n9/extref/ > >>>> nnano.2012.127-s2.txt . > >>>> > >>>> > >>>> Best wishes, > >>>> Dr. Maxim Arsent'ev > >>>> Laboratory of inorganic synthesis > >>>> Institute of Silicate Chemistry of RAS > >>>> > >>>> > >>>> 2013/11/18 Mahmoud Hammouri<m...@nmsu.edu <mailto:m...@nmsu.edu>> > >>>> > >>>> > >>>> You could also try to increase the non-equilibrium contour > >>>> points. > >>>> > >>>> Mahmoud > >>>> > >>>> > >>>> On Nov 18, 2013, at 11:22, "Sebastián Cauce do Dávila" > >>>> <sebastian.caic...@correounivalle.edu.co > >>>> <mailto:sebastian.caic...@correounivalle.edu.co>> wrote: > >>>> > >>>> Thank you very much for your suggestion. I will give it a > >>>> try! > >>>>> > >>>>> Sebastián Caicedo Dávila > >>>>> Bionanoelectronics research group > >>>>> School of electrical and electronics engineering > >>>>> Universidad del Valle > >>>>> Cali - Colombia > >>>>> > >>>>> > >>>>> On 18/11/2013, at 11:50, Максим Арсентьев > >>>>> <ars21031...@gmail.com <mailto:ars21031...@gmail.com>> > wrote: > >>>>> > >>>>> I also try some siesta only six months, but for a more > >>>>>> heterogeneous structure I noticed that the reduction > >>>>>> DM.MixingWeight reduces oscillations in convergence, so try > >>>>>> to play with it (decrease DM.MixingWeight). See > >>>>>> http://www.nature.com/nnano/journal/v7/n9/extref/nnano. > >>>>>> 2012.127-s2.txt > >>>>>> Maybe someone will tell something else. > >>>>>> > >>>>>> > >>>>>> 2013/11/18 Sebastian Caicedo > >>>>>> D.<sebastian.caic...@correounivalle.edu.co > >>>>>> <mailto:sebastian.caic...@correounivalle.edu.co>> > >>>>>> > >>>>>> > >>>>>> Dear Siesta/Transiesta users, > >>>>>> > >>>>>> I've been using the software for a couple months and > >>>>>> made some calculations of InAs and InP unit cell quite > >>>>>> successfully. Now I intend to work on transiesta > >>>>>> calculations of a heterostructure of both these > >>>>>> materials (InAs bulk with InP barriers). As a first > >>>>>> approach I want to simulate a couple of InAs unit cells > >>>>>> and the barriers shall be unit cells of InP, just to get > >>>>>> a qualitative idea. The electrodes .TSHS files were > >>>>>> obtained from the previous calculations of the InAs unit > >>>>>> cell. I wanted first to run a siesta calculation of the > >>>>>> whole heterostructure, so I can take a look at the > >>>>>> eigenvalues and define a correct value for the parameter > >>>>>> TS.ComplexContour.Emin, as suggested in the manual. > >>>>>> > >>>>>> The structure has 120 atoms and I'm using LDA > >>>>>> Pseudopotentials, obtained from the siesta webpage. (In > >>>>>> Pseudo includes semicore electrons, so we have enough > >>>>>> electrons to build a zinc-blende structure). The issue > >>>>>> is that after 1000 SCF steps, the energy doesn't > >>>>>> converge at all. I'm doing a Gamma-point calculation, > >>>>>> but even when I make the k-grid 1x1x15 it doesn't work > >>>>>> either. > >>>>>> > >>>>>> I used the same MeshCutoff as for the individual > >>>>>> materials unit cell an 200Ry and I increased the Energy > >>>>>> Shift, so the calculation would be a bit faster though > >>>>>> less precise. > >>>>>> > >>>>>> I attach the Input (INPUT.fdf, STRUCTURE.fdf) and output > >>>>>> files. > >>>>>> > >>>>>> I would really appreciate any suggestions. > >>>>>> > >>>>>> sincerely > >>>>>> > >>>>>> Sebastian Caicedo Davila > >>>>>> Bionanoelectronics Group > >>>>>> School of Electrical and Electronics Engineering > >>>>>> Universidad del Valle > >>>>>> Cali-Colombia > >>>>>> > >>>>>> > >>>>>> > >>>>>> > >>>>>> -- > >>>>>> Best wishes, > >>>>>> Dr. Maxim Arsent'ev > >>>>>> Laboratory of inorganic synthesis > >>>>>> Institute of Silicate Chemistry of RAS > >>>>>> > >>>>> > >>>> > >>>> > >>>> > >>>> -- > >>>> Best wishes, > >>>> Dr. Maxim Arsent'ev > >>>> Laboratory of inorganic synthesis > >>>> Institute of Silicate Chemistry of RAS > >>>> > >>> > >>> > >>> > >>> > >>> -- > >>> Best wishes, > >>> Dr. Maxim Arsent'ev > >>> Laboratory of inorganic synthesis > >>> Institute of Silicate Chemistry of RAS > >>> > >> > >> > >> -- > >> Herbert Fruchtl > >> Senior Scientific Computing Officer > >> School of Chemistry, School of Mathematics and Statistics > >> University of St Andrews > >> -- > >> The University of St Andrews is a charity registered in Scotland: > >> No SC013532 > >> > > > > > > > > -- > > Best wishes, > > Dr. Maxim Arsent'ev > > Laboratory of inorganic synthesis > > Institute of Silicate Chemistry of RAS > > > -- Best wishes, Dr. Maxim Arsent'ev Laboratory of inorganic synthesis Institute of Silicate Chemistry of RAS
ZrCeAl_forces_vs_CG_move.pdf
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